--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/paste_stencil.py	Sat Mar 28 15:57:33 2020 -0700
@@ -0,0 +1,49 @@
+import subprocess, os
+import bpy
+
+class PasteStencil(bpy.types.Operator):
+    """Paste system clipboard into a new stencil brush"""
+    bl_idname = "brush.paste_stencil"
+    bl_label = "Paste Stencil"
+
+    def execute(self, context):
+        png = subprocess.check_output([
+          'xclip', 
+          '-selection', 'clipboard', 
+          '-target', 'image/png', 
+          '-o']) 
+        for count in range(10000):
+            outPath = os.path.join(bpy.app.tempdir, 'paste-%d.png' % count)
+            if not os.path.exists(outPath):
+                break
+        else:
+            raise ValueError('out of filenames')
+        with open(outPath, 'wb') as f:
+            f.write(png)
+        tx = bpy.data.textures.new('paste0', 'IMAGE')
+        tx.image = bpy.data.images.load(outPath)
+        print('loaded %s' % outPath)
+        slot = bpy.data.brushes['TexDraw'].texture_slot
+        slot.texture = tx
+        slot.tex_paint_map_mode = 'STENCIL'
+            
+        return {"FINISHED"}
+
+
+def register():
+    bpy.utils.register_class(PasteStencil)
+
+def unregister():
+    bpy.utils.unregister_class(PasteStencil)
+
+bl_info = {
+    'name': 'Paste Stencil',
+    "version": (1, 0),
+    "blender": (2, 79, 0),
+    "location": "Brush",
+    "category": "Paint",
+}
+    
+if __name__ == "__main__":
+    register()
+    bpy.ops.brush.paste_stencil()